Dunnage bag having a mesh ply

ABSTRACT

A principal advantage of this composite bag compared to the bags disclosed in the present art using solid ply is improved combination of strength and flexibility. A composite dunnage bag being an elastic inner bag enclosed in a mesh outer bag. The bag replaces the system of state of the art bags plus filler panels which are currently used when the space between pallets is greater than 12 inches. The combination mesh and plastic is sufficiently strong and flexible to permit the bag to apply an 80% footprint against the cargo walls.

FIELD OF THE INVENTION

This invention relates to dunnage bag and particularly to a compositebag having an inner bladder and and outer mesh.

BACKGROUND AND INFORMATION DISCLOSURE

Products are commonly shipped as stacks of cargo on pallets placed inthe cargo space of an enclosure such as a truck trailer or container.After placing the cargo in the cargo space, it is generally necessary tosupport the cargo in the cargo space to prevent damage due to shifting

Common practice is to position two rows of cargo on pallets, each rowextending from the front to the rear of the container. The space betweenthe rows should contain braces to prevent shifting as described above.

“Dunnage bags”, large inflatable bags made of paper with an air tightplastic liner, have been used to prevent the shifting of cargo duringtransportation. These bags are placed in the space between the cargo andthe walls of the container or between neighboring rows of palletsholding cargo and then inflated. The bags are typically inflated to apressure of not more than 1½ to 2 pounds per square inch (psi). When thecargo arrives at its destination and prior to unloading, the bags arepunctured and discarded.

The problem of damage to cargo during transport has such a commonalityand severity that the American Association of Rail Roads has adoptedstandardized requirements for an acceptable protection system.

These requirements for dunnage bags include an “80% footprint”: where afootprint is the area of contact of the interface between the wall ofthe cargo and the bag. This specification satisfies the two requirementsthat the interface of the bag exert sufficient force over a broad areaof the bag to support the product without crushing the cargo such aswhen the cargo might be bags of fruit.

The A.A.R.R. has also developed a uniform testing procedure that anyshipping system must pass in order that the participating companyreceive the required approval from that Association to apply that systemas a basis for its shipping procedure.

The test, referred to herein as the AARR test, incorporated by referenceinto this specification, is described as follows:

1. A first railcar, loaded with 45,000 pounds, is positioned on arailroad track.

2. Additional railcars having a total weight of 275,000 pounds areaccelerated to a speed of 3 miles per hour and caused to slam into thefirst car.

3. This procedure is repeated a total of 3 times at speeds of 6 milesper hour each time.

4. The spacers are examined to determine any damage that has occurred tothe spacers such as rupture of dunnage bags, etc. The amount of movementis measured to determine the effetiveness of the air bags.

Various embodiments of dunnage bags have been disclosed for addressingrequirements of dunnage bags.

U.S. Pat. No. 3,427,995 to Stafford discloses an inflatable dunnage bagsystem positioned between cargo and the end bulkheads of railroad cars.This disclosure does not address the problem of filling space betweenrows of pallets parallel to the track.

U.S. Pat. No. 4,136,788 discloses a dunnage bag made of layers of paperwith flaps extending from the ends of the ply joined to the other wall.This invention suitable only where large overall thickness is requiredfor extra protection. and the “pinched end of the bag results indiminished contact (footprint) can be tolerated.

U.S. Pat. No. 4,553,887 to Reeves discloses a dunnage bag made oftriangular sheets of kraft paper lined with polyethylene.

U.S. Pat. No. 4,591,519 to Liebel discloses an airbag for bracing madeof a stiff paperboard having good vertical stiffness when uninflated.

U.S. Pat. No. 5,042,663 to Heinrick discloses joinable inflatablebladders for packaging.

U.S. Pat. No. 5,288,188 to Vanes discloses a dunnage bag constructed ofwelded rectangular sheets.

U.S. Pat. No. 5,372,396 to Nahmen discloses a cargo bed liner with sidepanels pivotally attached.

U.S. Pat. No. 5,431,525 to Sansone et al discloses a dual air bladderair bag.

U.S. Pat. No. 5,693,163 to Hoover et al discloses a method for makinginflated dunnage bags “on site” including unrolling a folded sheet andsealing step.

U.S. Pat. Nos. 5,868,534 and 5,788,438 to Boshorn et al discloses asealed bag inserted into a paper tube.

U.S. Pat. No. 5,908,275 to Howlett discloses an inflatable bagcomprising an inflatable inner bladder surrounded by a pair of paperplies.

None of the systems dunnage bags (inflated to 3 psi disclosed in theprior art perform satisfactorily when subject to the test sanctioned bythe AARR when the space between the parallel pallets is greater than 12inches. This is because, of a number of reasons including swelling ofthe bag toward the ceiling and because, when the space is greater than12 inches, an attempt to inflate the bag up to the 3 psi limit resultsin the bag not having enough surface area coverage and therefore notexerting enough force on the product.

Accordingly, the present practice for filling spaces having widthsgreater than twelve inches, is to occupy the additional space with“fillers”. Sheets of “honey comb” panel are commonly used for suchpurposes. However, the use of filler panels presents a number ofinconveniences including storage of the panel when not in use and theinconvenience associated with installing and removing the filler panelswhen loading and unloading the cargo space and extremely high cost ofthe fillers.

Rigid collapsible braces have been disclosed for supporting cargo incargo space. For example, U.S. Pat. No. 4,236,854 discloses a bracehaving side rails and extensible side arms

U.S. Pat. No. 4,473,31 to Wisecarver discloses a foot assembly andextensible element with lever locking member.

U.S. Pat. No. 5,181,815 to Haberkorn discloses a collapsible bracingstructure and rotatable latches for releasing.

U.S. Pat. No. 3,665,638 to James discloses a load brace with selectablefixed positions.

In view of the above, there continues to be intense interest inimproving the dunnage bags and systems presently on the market anddisclosed above in terms of reducing expense and inconvenience forfilling space between rows of pallets with product where the verticalwalls of cargo are spaced by more than twelve inches .

SUMMARY OF THE INVENTION

It is an object of this invention to provide a dunnage bag for fillingspaces between a pallet loaded with cargo and a neighboring palletloaded with cargo.

It is a further object to provide a bag that protects cargo on palletsduring transit when the the space between rows of cargo on pallets isgreater than 12 inches without the use of additional void fillers. Inthis situation, it is also an object that the bag surpasses therequirement of the A.A. R. R. rest for dunnage systems that protectcargo on pallets for transit

These requirements include developing a footprint of at least 80% whenthe bags are inflated to 1-3 pounds per square inch pressure.

This invention is directed toward a composite bag comprising aninflatable bag enclosed inside an outer mesh bag. The inner bagcomprises polypropylene sheet material about 0.10 mm thick especiallyformulated to have enhanced elasticity . The mesh comprises wovenpolypropylene. In use, the bag is positioned in the space between a pairof pallets, each loaded with cargo. The inner bag is inflated to fillthe space and support the bag during transit.

The inner polyethylene sheet material is sufficiently thin and flexibleto enable the inner bag to stretch without rupturing to the limitimposed by the mesh and contact 80% of the vertical cargo surface.

In a typical situation, the composite bag is inflated to 1½ psi. Thearea of the double bag facing the ceiling of the container is containedby the mesh so that bulging toward the ceiling of the container isminimal.

For spaces between stacks of cargo that are greater than 12 inches, useof the composite bag of this invention in place of the “standard” bagtogether with filler panels provides greater convenience and reducedcost for preventing shifting of cargo during transportation.

Each bag typically has an inlet valve adapted for admitting air into thebag from a pneumatic pump and a separate nipple with a cap wherein thenipple is large enough such that, when the cap is removed, the air isexpelled very quickly allowing quick and convenient deflation of the bagprior to unloading the cargo.

The method and features of this invention, and other aspects andadvantages will become better understood after studying the followingdescription, appended claims, and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. is a perspective view showing the composite structure of the bag.

FIG. 2 is an exploded view of the outer mesh bag.

FIG. 3 shows a truckbed with the dunnage bag between two rows of cargo.

DESCRIPTION OF PREFERRED EMBODIMENTS

Turning now to a discussion of the drawings, FIG. 1 shows the compositedunnage bag 10 of this invention including an inner inflatable bag 12and an outer mesh 14 enclosing the inner bag. The mesh 14 is partiallycut away to show the inner bag 12.

FIG. 1 shows the valve means for inflating and deflating the inner bagincluding a valve with a cap 20 on the side of the bag 10. which isattached to a source of pressurized air for filling the bag. The cap isremoved for fast deflating the bag 10 when the cargo is unloaded.

Nipples and valves are well known in the art and any one may be used inthis application.

The inner bag 12 comprises an extruded high density polyethylene tubewith vinyl acetate modification. Each end of the tube is heat sealed.The vinyl acetate modification increases elasticity of the inner bag.The tube has a wall 0.1 millimeters thick.

High density polyethylene sheet modified with vinyl acetate is availablefrom the Dupont Co.

The outer bag comprises woven polypropylene thread about 0.5 millimetersthick with about twelve threads per inch of weave

FIG. 2 shows the outer mesh bag exploded to show details of theconstruction. There is shown a single mesh panel 24 folded to form twobroad sections 24 A, B, a bottom section 26 and a top section 28. Thetwo meeting edges 30 are stitched together to form a mesh tube .

A pair of rectangular end mesh panels 32 are shown. Each end mesh panel32 has one edge 31 stitched to an end edge 33 of the mesh tube and anopposite edge stitched to an opposite end edge of the mesh tube. Theouter mesh bag is thereby formed having a substantially mattress shapewhen positioned in the space between the rows of cargo and the inner bagis filled with pressurized air.

FIG. 3 shows a truckbed 36 with two parallel rows 38 of loaded palletsand a dunnage bag 10 of the invention positioned between the rows 38.The present invention is specifically designed to accommodate a spaceselected from a range between 12 to 22 inches between the rows of cargo.

The dunnage bag of FIG. 2 is especially designed to fill a space betweenrows of cargo in a range of 12 to 22 inches when the mattress shape hasa width of about 20 inches. The height is typically selected from arange between 30 and 48 inches. The length selected from a range between48 and 102 inches.

There has been described a dunnage bag and method for use to achieve theobjects of the invention.

A principal advantage of this composite bag compared to the bagsdisclosed in the present art using solid ply is improved combination ofstrength and flexibility.

A mesh inherently has greater tear resistance and resistance to puncturethan does a solid sheet of the same weight.

The combination mesh container enclosing an inflatable bag has animproved ability to be inflated to where the composite bag fills in theirregular volume between rows of stacked products.

Variations and modifications may be suggested by reading thespecification and studying the figs. that are within the scope of theinvention. It is therefore wished to define the scope of the inventionby the appended claims and in view of the specification if need be.

What is claimed is:
 1. A dunnage bag for filling a space between twoparallel rows of cargo, said dunnage bag comprising: an air tight innerbag made of a flexible plastic sheet; a valve means for inflating anddeflating said inner bag; an outer bag made of a woven mesh andenclosing said inner bag; said outer bag further comprising a singlemain mesh panel folded to form two broad sides, a bottom side, and a topside with two opposite edges stitched together to form a tube; and saidouter bag further comprising a pair of rectangular side mesh panels,each side panel having one edge stitched to an end edge of said tube andan opposite edge stitched to one said end edge to provide that saidouter bag be formed having a substantially mattress shape whenpositioned in said space between said rows of cargo and said inner bagis filled with pressurized air.
 2. The dunnage bag of claim 1 whereinsaid space between rows of cargo is in a range of 12 to 22 inches andsaid mattress shape has dimensions about 20 inches wide, a heightselected from a range between 30 and 48 inches and a length selectedfrom a range between 48 and 102 inches.
 3. The dunnage bag of claim 1wherein said inner bag comprises an extruded high density polyethylenetube with vinyl acetate modification wherein each end of said tube issealed and whereby said vinyl acetate modification increases elasticityof said inner bag.
 4. The dunnage bag of claim 3 wherein said innerbagtube has a wall 0.1 millimeters thick.
 5. The dunnage bag of claim 1wherein said woven mesh comprises woven polypropylene thread about 0.5millimeters thick with about twelve threads per inch of weave.